Embodiments of the disclosed technology relate to an array substrate of a thin film transistor liquid crystal display and a method for manufacturing the same.
In the thin film transistor liquid crystal display (TFT-LCD) technology, Advanced-Super Dimensional Switching (AD-SDS) is one of the technologies for improving the display quality of a LCD.
An AS-SDS LCD forms a multi-dimensional space composite field by a parallel electric field generated by edges of pixel electrodes in the same plane and a vertical electric field generated between common electrodes and pixel electrodes, so that liquid crystal molecules between the pixel electrodes within a liquid crystal unit and immediately above the electrodes can rotate in all orientations, thereby improving work efficiency of in-plane orientation type liquid crystal and increasing the light transmission efficiency. AS-SDS can improve the display quality of a TFT-LCD, and has advantages of high transmittance, wide viewing angle, high aperture ratio, low chromatic aberration, short response time, free of push Mura, etc.
The main structure of a TFT-LCD typically comprises an array substrate and a color filter substrate forming a liquid crystal cell with a liquid crystal layer interposed therebetween. Gate lines, data lines, pixel electrodes, thin film transistors, and common electrodes of a strip structure are formed on the array substrate. A color resin pattern and a black matrix pattern are formed on the color filter substrate, and the black matrix pattern is mainly used to block the light leakage area. In the structure of an early AD-SDS TFT-LCD, the black matrix pattern on the color filter substrate is usually prepared with a resin material. A width of the black matrix is determined mainly based on the width of the data lines on the array substrate. With an improving requirement of LCD aperture ratio, the width of the data lines becomes narrower and narrower, so the black matrix of the resin material gradually becomes one of the main factors of blocking the increase of aperture ratio.
To increase aperture ratio, it has been proposed that the black matrix pattern is prepared with a metal material. Although this technology can reduce the width of the black matrix, the metal black matrix may lead to electric field distortion and reducing display quality of the AD-SDS TFT-LCD. To avoid electric field distortion, it has been proposed a technology of connecting the black matrix on the color filter substrate with the common electrode on array substrate. Specifically, during preparing the color filter substrate and the array substrate, via holes are opened in overcoat layers respectively so as to form transfer dots, the black matrix on the color filter substrate is electrically connected to the common electrode on array substrate through the transfer dots. However, in operation, this technology not only gives rise to high cost, but also incurs common electrode delay defect or the like. Firstly, it is necessary to have extra procedures and extra patterning apparatus for the fabrication of the transfer dots, so the production cost is increased. Secondly, since the common electrode and the black matrix are located on different substrates, respectively, and are connected with each other through the transfer dots, this structure causes a significant delay in the common electrode, and making this technology difficult for the application such as a large-sized display, a liquid crystal TV set, and so on.